Roof Turbines Seldom Turn

We have two new roof turbines that seldom turn. I noticed that neighbors on either side of us have turbines that turn even when the wind is not blowing. I don't believe theirs is powered.
Can someone help me with this problem? Can heat from the attic cause the turbines to turn or are they only turned by the wind?
Thanks, Mike
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White Horse wrote:

Rising air (usually heated) turns the turbines. Any pressure differential will cause them to turn, maybe even wind could rotate them at times. Turbines are a passive impediment to air flow, and their sole purpose is as a 'feel good' device to please their owners by showing some evidence of air movement. It would be more effective to use standard roof vents and if you must see whether something is happening to the air flow attach a few light plastic strips. Fluorescent colors would be a nice touch. Maybe your turbines could use some old fashioned lubrication.
Joe
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Joe wrote:

Blaze orange with purple polka-dots is my favorite.
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Joe wrote:

I can't find any reputable reference (or any reference at all) that says roof turbines are of miniscule value.
Turbines do move from 300 to 1300 cubic feet of air per minute out of the attic (at a wind speed of 5 to 15mph). Assuming 2000 sq ft with an average attic height of three feet, the 6000 cubic feet of air will be exchanged in four to twenty minutes. With two turbines, in two to ten minutes, etc. Four 14" turbines in a 15mph wind will change the air in the attic four times in five minutes.
One test I found showed an 8-foot ridge vent moving from 27 to 214 cu ft of air per minute, depending on the manufacturer. http://www.cor-a-vent.com/vent-air-flow-test.cfm
Admittedly, measuring apples and oranges: turbines depend on wind speed, vents depend on temperature differential and length of the vent. But it seems as if a single, 12" turbine is never less efficient than an eight-foot ridge vent and can be up to ten times better at moving air.
In other words, in a modest wind, turbines can move an ENORMOUS amount of air compared to a ridge vent.
The whole controverys seems like an easy thing, though, to test. If your home has turbines, put a thermometer in the attic. Then garbage-bag the turbine(s) for thirty minutes and check the thermometer. Is five, ten, twenty degrees worth it?
Now, as to the OP's original question: Give the turbine(s) a flick with your finger. They ought to spin like a roulette wheel! If they don't, they need leveling, lubricating, or replacing. Secondly, there's no rule that says you can't have BOTH ridge vents AND turbines. On my 3000 sq ft house I have ridge vents plus four 14" turbines.
And irrespective of which you choose, you can't have too much soffit venting.
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"HeyBub" wrote:

Your Physics teacher would give you a big hairy 'F' for a test like that. Those results can only show air flow vs. no air flow, so of course the lack of air flow will cause a higher temperature. A more defensible test would be to remove the whirly things on top of the turbine tubes and then watch the temperature drop, which it surely would. In the case of the stuck turbine, the thermometer in the attic will show a decline when the whirley thing is removed. Bet on it.
Joe
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Wind turbines must be installed absolutely vertical. Otherwise they bind and will not turn.

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neighbor might have fan blowing air out of attic turning fans.
sorry you wasted your money on the turbines......
they arent effective
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